OBMM:
1. Start up Oblivion Mod Manager.
2. Click the "Create" button near the bottom.
3. Click the "Add archive" button.
4. Use the browser to find and select the archived mod (the downloaded 7z file).
5. Click "Open" once you have found and selected the archived mod.
6. If you get a message about esps in sub directories, click "Yes". When asked if you would like to import OMOD creation data, click "Yes".
7. Click "Create omod". It will take some time to convert the archive to an OMOD.
8. Find the newly created OMOD on the list in the box to the right. Double click it.
9. Allow the installation process to guide you through setting up the mod. The mod will take some time to extract the necessary data.
10. You're done.